If war is the continuation of politics by other means, then the Internet is increasingly becoming the continuation of war by other means.

NATO’s Kosovo campaign ended with Serbian capitulation last June, but Serb-Kosovar animosities live on in cyberspace. Members of every ethnic group in the Balkans can find a welter of Web sites and newsgroups keeping their favourite conflicts alive. Programs called list servers pump out propaganda broadsides, recycle news dispatches and transmit full texts of official news conferences. Chat rooms offer forums for people who seem to like nothing better than to type invective at one another. And while the Balkan conflict seems to inspire the worst of the e-combat, wars big and small elsewhere in the world are also being fought via the Internet. In this sort of combat, at least, no one ends up dead.

Cyberwar can be deadly serious, though. During the war in Kosovo, hackers and spammers for the first time got involved in a big way, with assaults on rivals’ computer systems that enjoyed unprecedented successes.

Three days after NATO began bombing Yugoslavia, Belgrade hackers flooded the alliance computers in Brussels with e-mails, carrying attached viruses; NATO was forced to take its headquarters computers offline overnight.

Other Serb sympathizers hacked their way onto the White House official Web site, and after U.S. warplanes mistakenly bombed the Chinese Embassy, Chinese hackers posted graffiti on the home pages of the U.S. departments of the Interior and Energy, calling the American "Nazis."